How can I determine vscsi0 or vscsi1 is currently carrying data
through VIOS and VIOC.

Thanks a lot!

By default the Virtual I/O Client (VIOC) will use the first VIOS for
all VSCSI traffic. You can confirm which VSCSI adapter is being used by
starting nmon (on the VIOC) and
pressing the ‘a’ key. This will show which vscsi adapter is currently in use.
e.g.

Use the lspath command to determine the current path priority for a hdisk.
By default it will be set to 1 for both adapters, meaning that traffic will go
via the first path. Priority 1 is the highest priority, and you can define a
priority from 1 to 255.

# lspath
-AE -l hdisk2 -p vscsi2

priority 1
Priority True

# lspath
-AE -l hdisk2 -p vscsi3

priority 1
Priority True

You can change the path priority of a hdisk using the chpath command. For example, we change
the priority for vscsi2 to 255, so that vscsi3 now has the highest priority:

# chpath -l
hdisk2 -a priority=255 -p vscsi2

# chpath -l
hdisk2 -a priority=1 -p vscsi3

This will change the path priority for hdisk2 so that its traffic will
use vscsi3 instead vscsi2.